Depending on engine type, motor vehicles require different fuels, wherein refuelling the motor vehicle with an unsuitable fuel can cause enormous damage to the motor vehicle.
Conventional motor vehicles are normally refuelled at filling stations. The pumps at modern filling stations usually offer several types of fuel, normally diesel and petrol with different octane ratings.
A first step for preventing incorrect refuelling was the introduction of pump valves with different diameters now, for example, diesel pump valves have a diameter of ≧23.6 mm, petrol pump valves however have a diameter of less than 21.3 mm.
Pump valves are colloquially called filler nozzles and are connected to the fuel filler pump via a hose.
By adapting the diameter of the motor vehicle tank connection (tank filler pipe), at least on petrol-powered motor vehicles, incorrect refuelling with diesel can be prevented in a simple manner.
The risk of accidentally introducing petrol, which is delivered through a petrol filler nozzle smaller than a diesel filler nozzle, into a diesel-powered vehicle however persists.
The general prior art describes for this problem a number of different solutions for preventing incorrect refuelling of a diesel-powered motor vehicle with petrol.
German Patent Publication No. DE 103 20 992 A1, for example, describes a device wherein an additional device is introduced into the tank connector of a vehicle. The annular additional device reduces the diameter of the tank connector by way of a plurality of radial elements arranged around the periphery. In the region of the radial elements, the diameter is smaller than the diameter of the suitable filler nozzle. The additional device is designed tapering upward towards the opening so that the suitable filler nozzle can be introduced easily and simply. On further insertion of the suitable filler nozzle, the radial elements are deformed, tipped or moved such that the opening expands and the filler nozzle can be pushed fully into the tank pipe. The elastic or articulated movement of the radial elements causes a tilting or rotational movement of counterhooks on the device. An unsuitable filler nozzle remains attached to the counterhooks and cannot be introduced further into the filler pipe.
German Patent Publication No. DE 101 57 090 C1 also describes an arrangement for preventing refuelling of a diesel vehicle with lead-free petrol. A blocking lever is provided in the tank connector which is movable to and fro between a rest position and a refuelling position. At its end facing away from the tank opening, the blocking lever is provided with a blocking tab which in the rest position protrudes into the cross section of the tank connector and prevents insertion of an unsuitable filler nozzle into the tank. At its end facing the tank opening, the blocking lever may have an actuation extension which can be actuated by a suitable filler nozzle and moves the blocking lever into a refuelling position.
Further devices concerned with this topic are disclosed amongst others in German Patent Publication No. DE 20200502 1965 and European Patent Publication No. EP 1790517.